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		<center><h3>Creation of a Pendulum (2/8)</h3></center>		
        <div id="orangeText">Description</div>		
         
         <p>In the previous scene, no solver was present, so no simulation was done. In this step, we will add an <strong>ODE solver</strong> in the Root node of the simulation. We provide several ODE solvers, with different integration schemes. Take a look at our tutorials on Solvers later.</p>

		<div id="orangeText">Key points</div>		                
                
         <p>We will use the classic explicit euler solver <strong>EulerSolver</strong> to update particle positions and velocities at each time step. In SOFA, a solver acts on all the object placed below in the hierarchy. </p>
         
         <p><div id="tutorialAction">In the Modeler's <strong>Filter</strong> textbox, type "Euler". Click and drag the EulerSolver component over the <strong>root</strong> node. Press the <strong>Run in SOFA</strong> button. Press <strong>Animate</strong>.</div></p>   

		<br><div id="orangeText">Results</div>
         <p>       This time, when you animate the scene, the particule falls along the direction of the gravity.<br>
                The gravity is specified in the root node of the simulation. We use a default value of (0, 0, -9.81).</p>
                
         <p><div id="tutorialAction">In the Modeler scene graph, double click the root node.</div></p>
         
         <p>This opens the components for this node, and allows you to edit them. We won't make any changes for now.</p>

		 <p><div id="tutorialAction"> Press <strong>OK</strong> to return to the Modeler window. </div></p>
            
          <p>Changing the gravity on child nodes of the simulation will not do anything as at each time step the gravity, and other parameters, (time, dt...) is overwritten using the value specified in the root node.<br>
             The component Gravity lets you specify a particular gravity for a node and all its children.</p> 
     
		 <p><div id="tutorialAction"> To see an example of this, type "Gravity" into the <strong>Filter</strong> textbox in the Modeler. Click on the <strong>Gravity</strong> component. In the top right section of the window, a description of the component will appear, with links to examples. Click on the links to open the example scene in the Modeler. When you are done, close the <strong>Gravity.scn</strong>  tab to return to the tutorial scene. </div> </p>  

                <br><center><h3><a href="0_Pendulum.scn">Previous</a> ____________  <a href="2_Pendulum.scn">Next</a></center></h3>
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